Bilge pump dump below water line

[boydgatlin]

Why on earth would a sailboat designer/manufacturer put the thru-hulls for both the manual and automatic bilge pumps below the water line? Seems like asking for unnecessary risk. This is exactly what we have on our 42 ft CC Beneteau, made in France. In addition, the associated seacocks are accessible only by removing panels held in place by 4-6 screws. I can imagine the scramble to get to them should a hose or clamp fail. One is accessed through a lazerette, and the other is beneath the propane locker via the aft cabin. The only defense would seem to be keeping the hoses, seacocks, and clamps in pristine condition at all times, despite the inconvenient access.

Does anyone know if a significant number of other boats have underwater bilge thru-hulls? What could possibly be the rationale for the arrangement?

[merttan]

Originally Posted by boydgatlin

The only defense would seem to be keeping the hoses, seacocks, and clamps in pristine condition at all times, despite the inconvenient access.

That's exactly what they want the boat owners to do...

No actually, they may be trying to make hull look good all times... Like no water marks on the hull from a above waterline outlet...

They might figured that if the bilge pump doesn't allow siphoning water back in they should be ok...

As I said, if the bilge pump has a oneway outlet and a high loop, then a seacock on the throughhull, it should be fine... You said access was covered, that doesn't make any sense...

I've seen lots of through hulls, those might be bilge pump oulets, below water line...

[Stillraining]

All my boats were above water line both power and sail so Im no help...I agree with both your concerns...My bilge pump lines are thin wall and not designed to keep water pressure out...I would have to take a guess that they at least put a vented loop and a check valve in that design?....But on a nice boat such as yours I would personally change both issues if it were me...

[BenthosCritter]

The head discharge is below the waterline so that one does not have to smell the effluent. Bypassing the holding tank should only be done where it is legal. If the bowl of the head is still above waterline when heeling, then siphoning is not a problem.